A detailed quantification of differential ratings of perceived exertion during team-sport training

Hypoxia matters: comparison of external and internal training load markers during an 8-week resistance training program in normoxia, normobaric hypoxia and hypobaric hypoxia

PURPOSE

To compare external and internal training load markers during resistance training (RT) in normoxia (N), intermittent hypobaric hypoxia (HH), and intermittent normobaric hypoxia (NH).

METHODS

Thirty-three volunteers were assigned an 8-week RT program in either N (690 m, n = 10), HH (2320 m, n = 10), or NH (inspired fraction of oxygen = 15.9%; ~ 2320 m, n = 13). The RT program (3x/week) consisted of six exercises, with three sets of six to 12 repetitions at ~ 70% of one repetition maximum (1RM) with the first session of each week used for analysis. 1RM in back squat and bench press was used to evaluate muscle strength before and after the program. External load was assessed by the volume load relative to body mass (RVL, kg·kg-1). Internal load was assessed by the ratings of perceived exertion (RPE) and heart rate (HR).

RESULTS

Smaller relative improvements were found for the back squat in the N group (11.5 ± 8.8%) when compared to the NH group (22.2 ± 8.2%, P = 0.01) and the HH group (22 ± 8.1%, P = 0.02). All groups showed similar RVL, HR responses and RPE across the program (P˃0.05). However, reduced HR recovery values, calculated as the difference between the highest HR value (HRpeak) and the resting heart rate after a two min rest, were seen in the N and NH groups across the program (P < 0.05).

CONCLUSION

It seems that 8 weeks of intermittent RT in hypoxic environments could maximize time-efficiency when aiming to improve strength levels in back squat without evoking higher levels of physiological stress. Performing RT at hypobaric hypoxia may improve the cardiorespiratory response, which in turn could speed recovery.

Relationship Between External Training Load and Session Rating of Perceived Exertion Training Impulse in Elite Sprinters

PURPOSE

To quantify the change in session rating of perceived exertion training impulse (RPE-TRIMP) that may occur in response to increased running distance at 3 running velocity ranges in elite sprinters.

METHODS

We monitored training load in elite sprinters (women: n = 7; men: n = 11) using wearable Global Positioning System technology and RPE-TRIMP for a total of 681 individual training sessions during a 22-week competition-preparation period. Internal training load was operationalized by RPE-TRIMP, and external training load was operationalized by distance covered in 3 velocity ranges. A linear mixed-effects model with athlete as a random effect was fit to RPE-TRIMP with total distance covered at ≤69.99% (low-velocity running [LVR]), 70% to 84.99% (high-velocity running [HVR]), and 85% to 100% (very-high-velocity running [VHVR]) of individual maximum velocity.

RESULTS

Increased running distance in all 3 velocity ranges (LVR, HVR, and VHVR) resulted in a significant (P < .001) increase in RPE-TRIMP. Coefficients (95% CIs) were .10 (.08-.11) for LVR, .23 (.18-.28) for HVR, and .44 (.35-.53) for VHVR. A 50-m increase in running distance covered in the LVR, HVR, and VHVR velocity ranges was associated with increases in RPE-TRIMP of 5, 11.5, and 22 arbitrary units, respectively.

CONCLUSIONS

Internal training load, calculated as RPE-TRIMP, increased with increases in total distance covered in the LVR, HVR, and VHVR velocity ranges (P < .001). RPE-TRIMP can be a practical solution for monitoring global training-session load in elite sprinters.

Match-to-Match Variation on High-Intensity Demands in a Portuguese Professional Football Team

The aim of this study was to analyze the match-to-match variation in high-intensity demands from one Portuguese professional football team according to playing positions. Twenty-three male outfield professional football players were observed during eighteen matches of the Portuguese Second League. Time-motion data were collected using Global Positioning System (GPS) technology. Match running performance was analyzed based on the following three playing positions: defenders (DF), midfielders (MF), and forwards (FW). Repeated measures ANOVA was utilized to compare match running performance within each position role, and seasonal running variation. Practical differences were assessed using the smallest worthwhile change (SWC), coefficient of variation (CV), and twice the coefficient of variation (2CV). Significant differences were found among playing positions in total distance covered (F = 15.45, p < 0.001, η2 = 0.33), average speed (F = 12.79, p < 0.001, η2 = 0.29), high-speed running (F = 16.93, p < 0.001, η2 = 0.36), sprinting (F = 13.49, p < 0.001, η2 = 0.31), accelerations (F = 4.69, p = 0.001, η2 = 0.132), and decelerations (F = 12.21, p < 0.001, η2 = 0.284). The match-to-match running performance encompassed TD (6.59%), AvS (8.67%), HSRr (37.83%), SPR (34.82%), ACC (26.92%), and DEC (27.85%). CV values for total distance covered ranged from 4.87-6.82%, with forwards and midfielders exhibiting the greatest and smallest variation, respectively. Midfielders demonstrated the highest match-to-match variation for all other analyzed variables (8.12-69.17%). All playing positions showed significant variation in high-demanding variables (26.94-37.83%). This study presents the initial analysis of match-to-match variation in high-intensity demands within a Portuguese professional football team. Thus, the position's specificity and context can provide a helpful strategy for evaluating match-to-match running performance, and for recommending individualized training exercises based on the peak and high-intensity demands for each player's role within the game.

Maturity status influences perceived training load and neuromuscular performance during an academy soccer season

Commonly we see large within-age-group variations in physique, including body mass, stature, and percentages of predicted adult height, which suggests that age-specified training loads are flawed. Aims were to investigate how maturation impacts training load and neuromuscular response within academy soccer and to provide recommendations for practitioners. Fifty-five male soccer players (age 14.5 ± 1.2 years; stature 172 ± 10 cm; body mass 59.8 ± 10 kg; 94.1 ± 1.8% predicted adult height) reported differential ratings of perceived exertion (AU) across a season. Neuromuscular performance (countermovement jump, reactive strength index, absolute and relative leg stiffness) was measured at three time points across the season. Perceived exertion and neuromuscular performance were examined using linear mixed modelling, supplemented with non-clinical magnitude-based decisions. Analysis indicates every 5% increase in maturity status results in players perceiving overall session intensity 6.9 AU lower and 13.9 AU lower for a 10% maturity shift. Both 5% and 10% changes in maturity most likely resulted in higher countermovement jump, with likely to very likely differences observed for RSI and ABS. Maturity substantially influences neuromuscular performance over the season. Therefore, maturity-specific load prescription may prevent significant within age-group differences in accumulated load, possibly reducing injury risk and/or burnout.

Bone health, body composition and physical fitness dose-response effects of 16 weeks of recreational team handball for inactive middle-to-older-aged males - A randomised controlled trial

In this study we aimed at analysing the effects of different weekly exercise volumes (1, 2 or 3 times 60-min) on bone health, body composition and physical fitness of inactive middle-to-older-aged males, after 16 weeks of recreational team handball (RTH). Fifty-four men (68 ± 4 years, stature 169 ± 6 cm; body mass 78.4 ± 10.7 kg; fat mass 27.1 ± 5.3%; BMI 27.4 ± 2.9 kg/m2; VO2peak 27.3 ± 4.8 mL/min/kg) were randomised into three intervention groups (TH1, n = 13; TH2, n = 15; or TH3, n = 12, performing 1, 2 and 3 weekly 60-min training sessions, respectively), and a control group (CG, n = 14). The training sessions consisted mainly of RTH matches played as small-sided and formal game formats (4v4, 5v5, 6v6 or 7v7) with adapted rules. Matches' mean and peak heart rate (HR) ranged from 78-80% and 86-89%HRmax, respectively, and distance covered from 4676 to 5202 m. A time x group interaction was observed for procollagen type-1 amino-terminal propeptide (P1NP), osteocalcin (OC), carboxy-terminal type-1 collagen crosslinks (CTX), sclerostin, upper and lower body dynamic strength, right arm fat mass, left and right arm, right leg and android total mass (TM; p ≤ 0.047) with the greatest effects being shown for TH2 and TH3 groups. Post-intervention group differences were observed in CTX, left arm and right leg TM (TH3 > TH1), P1NP (TH2 > CG), OC, right arm TM (TH3 > CG), upper (CG < TH1, TH2 and TH3) and lower body dynamic strength (CG < TH1 and TH3) (p ≤ 0.047). RTH was effective in enhancing bone health, body composition and physical fitness in middle-to-older-aged males, especially for the intervention groups that performed 2-3 weekly training sessions.ClinicalTrials.gov ID: NCT05295511.Trial registration: ClinicalTrials.gov identifier: NCT05295511.HighlightsAfter 16 weeks of recreational team handball small-sided and formal matches, inactive middle-to-older-aged males improved bone health, body composition and physical fitness, by performing 1, 2 or 3 60-min weekly sessions, however, greater improvements were shown in the groups that performed 2 or 3 weekly training sessions.Training intensity was similar across the intervention groups that performed recreational team handball for 1, 2 or 3 60-min weekly sessions, which means that training volume is most likely to be the reason for the different health effects shown.The very high fun levels reported by all intervention groups shows that recreational team handball is a social and fun exercise modality for middle-to-older-aged males, with potential to intrinsically motivate the participants and assure long-term adherence to exercise.

Inconsistent Effect of Psychometric-Scale Familiarization on the Relationship Between Ratings of Perceived Exertion and External Load Measures in Elite Youth Soccer Players

OBJECTIVES

To examine the moderating effect of familiarization on the relationship between external load and ratings of perceived exertion (RPEs) in elite youth soccer players.

METHODS

Thirty-five elite male youth soccer players were monitored over a 31-week period. Players had no previous experience using the centiMax scale (arbitrary units [AU]). The final sample included familiarized (blackness test; n = 20) and nonfamiliarized players (n = 15) with the Borg centiMax scale. Players recorded a global RPE and differential RPEs (dRPE) for breathlessness (RPE-B) and leg-muscle exertion (RPE-L) 15 to 30 minutes following training sessions and competitive matches. Separate multivariable-adjusted random-effects generalized additive models with restricted maximum likelihood quantified familiarization versus no-familiarization differences in actual perceived exertion score (in AU) by number of accelerations, decelerations, and high-speed running distance (in meters) as predictor variables, respectively.

RESULTS

Players improved their blackness test score from 39% to 78%. For explorations by number of accelerations, familiarization effects were not practically relevant for the RPE and RPE-B variables. The width and sign of the effects for the RPE-L variable at 30 efforts of 10 AU (95% CI, 4-16 AU) suggested that scores were lower for players who underwent familiarization versus players who did not. Familiarization effects were not practically relevant for any RPE variable irrespective of the number of deceleration efforts and high-speed running distance covered.

CONCLUSION

Improved performance on the blackness test did not have a moderating effect on the relationship between proxy measures of external load and RPEs.

A random forest approach to explore how situational variables affect perceived exertion of elite youth soccer players

The aim of this study was to explore how situational variables affect youth soccer players' perceived exertion (RPE) after official matches. Thirty-five elite youth male players (14.33 ± 0.86 years; 173.49 ± 6.16 cm; 63.44 ± 5.98 kg) who belonged to two different teams of a professional club participated in this study. Data collection was conducted during two seasons (2016-2017, 2017-2018) and included 60 official matches (30 official matches per team). Ten minutes after each match players rated their RPE and using a modified Borg CR-10 scale. A Random Forest Regression was used to quantify the importance of match-related situational variables in RPE. Afterwards, a linear mixed model analysis was applied to identify the variability in RPE among the situational variables. The game-playing time, the player status (starter or substitute) and the player identity were the strongest predictors of RPE. Moreover, the match outcome and the final scoreline showed significant effects on both starter and substitute players but the main effect of the quality of the opponent was only identified in starter players (p < 0.05). These results allow practitioners to know how situational variables interact and modulate RPE after official matches and help them to prescribe and adapt the players' training content and load before and after matches.

Mixed-gender small-sided recreational team handball games in middle-aged and elderly are physiologically more demanding for women than men

This study examined the physical and physiological demands and perceived experience of a multicomponent exercise mode, recreational team handball (TH), for middle-aged/elderly men and women, played as same- vs. mixed-gender 6v6 game formats. Matches' heart rate (HR), blood lactate (BL), perceived experience, activity profile, player load and accelerometer variables were assessed. Forty-one participants, with at least 12 weeks of experience with recreational TH (22 men; 69±4 years, 19 women; 66±6 years), performed 2 same- and 2 mixed-gender matches on an indoor 40x20 m TH court. A game format-by-gender interaction was observed for mean HR (%HRmax), time spent ˃80 and ˃90%HRmax, respiratory rating of perceived exertion and for several of the external load variables (p≤0.05). During mixed-gender matches, time spent ˃80 and ˃90%HRmax, was higher for women vs. men (p≤0.017). During same- and mixed-gender matches, BL was lower for women than men (p≤0.015). Time spent ˃90%HRmax was lower for women (p = 0.036), whereas time spent ˃80%HRmax was higher for men during same- vs. mixed-gender matches (p = 0.034). The frequency, %total match time and distance covered with high-demanding movements were higher for men during same-gender than during mixed-gender matches (p≤0.036), and higher for men vs. women in same- and mixed-gender matches (p≤0.046). The frequency of high-intensity actions, accelerations, time spent in the higher player load zones and total accumulated player load, were higher for men vs. women during same- and mixed-gender matches (p≤0.044). Fun levels were very high (9.1-9.3 AU, 0-10). Mixed-gender small-sided recreational TH games are physiologically more demanding for middle-aged/elderly women compared to men. Men showed higher cardiovascular and activity profile demands when playing same-gender matches, which was opposite to women. Nevertheless, TH is a high-intensity and motivating exercise mode for both genders, regardless the gender game format, meaning that exercise interventions may use same- and mixed-gender matches to promote participants' health.

Elite North American soccer performance in thermally challenging environments: An explorative approach to tracking outcomes

AIMS

The physiologic challenges related to performances in hot conditions calls for dedicated consideration when planning athlete training, although complete amelioration of the effects of heat may not be possible. We aimed to quantify within-subject correlations between different measures of environmental temperature and performance changes over multiple elite soccer competitions.

METHODS

Thirty-seven elite male soccer players (age: 26 ± 3.4 years, height: 171 ± 2 cm, body mass: 78 ± 7.1 kg) competed in North America over four seasons (range: 3 to 98 matches). Players wore global positioning system devices during games and reported differential-RPE immediately post game. Temperatures at kick-off, week average temperature, the difference between game-day and week average (DiffTemp), and heat index at kick-off were obtained. Within-player correlations were calculated using general linear models to quantify associations between fluctuations in temperature measures and physical and perceived outputs.

RESULTS

Correlations between total distance and the various temperature measures were trivial to small (range: -0.08 to 0.13, p=<0.001-0.02). Small negative correlations were found between all temperature measures except DiffTemp and high-speed running (HSR) (range: -0.17 to -0.14, p=<0.001). Most correlations between differential-RPE and temperature measures were trivial to small and not significant (r = 0.06 to 0.18 p = 0.03-0.92) although breathlessness-RPE and heat index showed a small significant association (P = 0.018).

CONCLUSION

Decrements in HSR appear to be associated with increased environmental temperature, however, these associations are small in magnitude.

Subjective Measures of Workload and Sleep in Australian Army Recruits; Potential Utility as Monitoring Tools

INTRODUCTION

Subjective measures may offer practitioners a relatively simple method to monitor recruit responses to basic military training (BMT). Yet, a lack of agreement between subjective and objective measures may presents a problem to practitioners wishing to implement subjective monitoring strategies. This study therefore aims to examine associations between subjective and objective measures of workload and sleep in Australian Army recruits.

MATERIALS AND METHODS

Thirty recruits provided daily rating of perceived exertion (RPE) and differential RPE (d-RPE) for breathlessness and leg muscle exertion each evening. Daily internal workloads determined via heart rate monitors were expressed as Edwards training impulse (TRIMP) and average heart rate. External workloads were determined via global positioning system (PlayerLoadTM) and activity monitors (step count). Subjective sleep quality and duration was monitored in 29 different recruits via a customized questionnaire. Activity monitors assessed objective sleep measures. Linear mixed-models assessed associations between objective and subjective measures. Akaike Information Criterion assessed if the inclusion of d-RPE measures resulted in a more parsimonious model. Mean bias, typical error of the estimate (TEE) and within-subject repeated measures correlations examined agreement between subjective and objective sleep duration.

RESULTS

Conditional R2 for associations between objective and subjective workloads ranged from 0.18 to 0.78, P < 0.01, with strong associations between subjective measures of workload and TRIMP (0.65-0.78), average heart rate (0.57-0.73), and PlayerLoadTM (0.54-0.68). Including d-RPE lowered Akaike Information Criterion. The slope estimate between objective and subjective measures of sleep quality was not significant. A trivial relationship (r = 0.12; CI -0.03, 0.27) was observed between objective and subjective sleep duration with subjective measures overestimating (mean bias 25 min) sleep duration (TEE 41 min).

CONCLUSIONS

Daily RPE offers a proxy measure of internal workload in Australian Army recruits; however, the current subjective sleep questionnaire should not be considered a proxy measure of objective sleep measures.

Concentric Phase Assistance Enhances Eccentric Peak Power During Flywheel Squats: Intersession Reliability and the Linear Relationship Between Concentric and Eccentric Phases

BACKGROUND

It remains unknown if flywheel-assisted squats can be reliably utilized to increase power outputs and if such outputs are related.

OBJECTIVES

To compare assisted and unassisted flywheel squat peak power outputs, determine their reliability, and analyze the relationship of the delta difference between peak power outputs during the squats.

METHODS

Twenty male athletes attended the laboratory 6 times-performing 3 sets of 8 repetitions of assisted and unassisted squats during 2 familiarization sessions and then 3 sets of 8 repetitions during experimental sessions 3 to 6 (2 sessions for unassisted and assisted squat in randomized order, respectively).

RESULTS

Concentric and eccentric peak power were significantly greater during assisted squats (both P < .001, d = 1.59, d = 1.57, respectively). Rating of perceived exertion (P = .23) and eccentric:concentric ratio (P = .094) did not differ between squat conditions. Peak power measures obtained excellent reliability, while rating of perceived exertion and eccentric:concentric ratio estimates were rated as acceptable to good, with greater uncertainty. A large to very large correlation (r = .77) was found between concentric and eccentric peak power delta difference of assisted and unassisted squats.

CONCLUSIONS

Greater concentric outputs during assisted squats induce greater eccentric outputs and obtain greater mechanical load. Peak power is a reliable metric for monitoring flywheel training, whereas the eccentric:concentric ratio should be used with caution. Eccentric and concentric peak power are strongly related during flywheel squats, evidencing the need to maximize the concentric output to enhance the eccentric output.

Effects of match contextual factors on internal and external load in elite Brazilian professional soccer players through the season

This study aimed to investigate the effects of contextual match factors (quality of opposition, match outcome, change of head coach or playing style) on internal and external load in elite Brazilian professional soccer players, considering the total and effective playing time. Twenty-two professional male outfield soccer players participated in this study (age 28.4 ± 4.9 years; height 1.78 ± 0.1 cm; body mass 72.9 ± 7.1 kg). The internal (rating of perceived exertion-based load [sRPE]) and external load (distance and accelerometry-based measures) were recorded during 38 matches, over the 2021 season of the Brazilian National 1st Division League using a global position system (10 Hz) integrated with an accelerometer (200 Hz). The main results were: (i) matches played against weak opponents presented greater values of sprinting distances compared to matches against intermediate and strong opponents; (ii) players covered greater high-intensity running distances when drawing than winning the matches; (iii) matches with assistant coaches presented higher mean speed relative to effective playing time (MSEPT) compared to coach 1 and coach 2 conditions. In addition, players covered greater MSEPT and high-acceleration in matches with coach 2 vs. coach 3; (iv) finally, small positive correlations were observed between positional attack sequences and MSTPT, total distance covered, and acceleration. Coaches and practitioners should consider these results when interpreting external load variables during elite Brazilian soccer matches.

Acute physiological response to different recreational team handball game formats in over 60-year-old inactive men

This study described the physical and physiological demands, activity profile and fun levels of recreational team handball (TH) game formats in over 60-year-old men with no previous experience with this sport (n = 17, 67.4±3.3 years). The participants performed 5v5, 6v6 and 7v7 matches (3x15-min periods) with fixed pitch size (40x20 m). In all testing sessions, heart rate (HR), differential ratings of perceived exertion and blood lactate were evaluated to measure internal load. Locomotor profile, game actions and accelerometer data were used to access external load. Also, fun levels were registered at the end of all testing sessions. Mean (76-77%HRmax) and peak HR (84-86%HRmax) decreased from the first to the third match period, in 6v6 and 7v7 (p≤0.034, d = 0.730). Blood lactate increased from baseline to the first period and decreased from the first to the third period in all game formats (p<0.001, d = 1.646). The participants covered longer total distances in 6v6 vs 5v5 (p≤0.005, d = 0.927) and spent more time in fast running in 6v6 vs 5v5 and 7v7 (p<0.001, d = 1.725) and in 5v5 vs 7v7 (p = 0.007, d = 0.912). A higher number of throws was performed in 5v5 vs 6v6 and 7v7 (p<0.001, d = 1.547), and in 6v6 vs 7v7 (p = 0.031, d = 0.779). The number of stops and total actions in 7v7 was significantly lower vs 5v5 and 6v6 (p≤0.003, d = 1.025). Recreational TH is a high-intensity and motivating exercise mode for middle-aged and older men, regardless the game format. However, higher high-intensity demands were observed during 5v5 and 6v6 game formats. Therefore, it is suggested a multiple game format (5v5, 6v6 and 7v7) training plan, with more use of 5v5 and 6v6 game formats, with training sessions lasting up to 15-min of warm-up and 3x15-min periods of match-play, when prescribing recreational TH to improve cardiovascular and musculoskeletal health in this population.

The Maximal Intensity Period: Rationalising its Use in Team Sports Practice

Quantifying the highest intensity of competition (the maximal intensity period [MIP]) for varying durations in team sports has been used to identify training targets to inform the preparation of players. However, its usefulness has recently been questioned since it may still underestimate the training intensity required to produce specific physiological adaptations. Within this conceptual review, we aimed to: (i) describe the methods used to determine the MIP; (ii) compare the data obtained using MIP or whole-match analysis, considering the influence of different contextual factors; (iii) rationalise the use of the MIP in team sports practice and (iv) provide limitations and future directions in the area. Different methods are used to determine the MIP, with MIP values far greater than those derived from averaging across the whole match, although they could be affected by contextual factors that should be considered in practice. Additionally, while the MIP might be utilised during sport-specific drills, it is inappropriate to inform the intensity of interval-based, repeated sprint and linear speed training modes. Lastly, MIP does not consider any variable of internal load, a major limitation when informing training practice. In conclusion, practitioners should be aware of the potential use or misuse of the MIP.

Examination of differential ratings of perceived exertion (dRPE) during bio-banded small-sided games

The aims of the current study were to investigate the use of dRPE with academy soccer players to: 1) examine the effect of bio-banded and non-bio-banded maturity groups within SSG on players dRPE; 2) describe the multivariate relationships between dRPE measures investigating the sources of intra and inter-individual variation, and the effects of maturation and bio-banding. Using 32 highly trained under (U) 12 to U14 soccer players (mean (SD) age 12.9 (0.9) years, body mass 46.4 (8.5) kg and stature 158.2 (14.9) cm) academy soccer players from two English professional male soccer academies. Players were categorised according to somatic maturity status using estimated percentage of adult stature attainment, with players randomly assigned into teams to play 4v4 SSG. The study used a repeated measures design, whereby the selected players participated within 6 bio-banded (maturity matched [pre-PHV Vs pre-PHV and post-PHV vs post PHV] and miss-matched [pre-PHV vs post-PHV] and 6 mixed maturity SSG at their respective clubs. Using mixed and fixed effect regression models, it was established hat pre-PHV players exhibited higher dRPE compared with their post-PHV counterparts. Mixed bio-banded games reported higher dRPE outputs overall. Variation in dRPE measures across a series of bio-banded games are caused by both between and within sources of variation in relatively equal amounts. Across a series of bio-banded games, the four dRPE measures do not provide unique information, and between variation is best expressed by one or two highly correlated components, with within variation best explained by a single equally loaded component. Using a bio-banding SSG design study, we have shown that pre-PHV players report higher subjective measures of exertion than post-PHV players during. Additionally, when evenly mixing players based on measures of maturation, higher measures of perceived exertion were generally reported.

Photobiomodulation Therapy Combined with a Static Magnetic Field Applied in Different Moments Enhances Performance and Accelerates Muscle Recovery in CrossFit® Athletes: A Randomized, Triple-Blind, Placebo-Controlled Crossover Trial

The ergogenic effects of photobiomodulation therapy combined with a static magnetic field (PBMT-sMF) on exercises with characteristics similar to those of CrossFit® are unknown. This study was aimed at investigating the effects of PBMT-sMF applied at different times on recovery and physical performance in CrossFit® athletes by analyzing functional aspects, muscle damage, inflammatory processes, and oxidative stress. This was a prospectively registered, triple-blinded, placebo-controlled, crossover trial. CrossFit® athletes were recruited and assigned to receive one of the four possible interventions. Each intervention included protocols before and after the exercise (referred to as the workout of the day (WOD)). The four possibilities of intervention were as follows: placebo before and after WOD (placebo), PBMT-sMF before and placebo after WOD (PBMT-sMF before), placebo before and PBMT-sMF after WOD (PBMT-sMF after), and PBMT-sMF before and after WOD (PBMT-sMF before and after). The order of possibilities for the interventions was randomized. The primary outcome was the functional test performance. The secondary outcomes were the subjective perception of exertion, muscle damage, inflammation, and oxidative stress. The outcomes were measured before the WOD; immediately after the intervention; and 1, 24, and 48 hours after the WOD. Statistical analysis was performed using repeated measures ANOVA followed by the Bonferroni post hoc test to examine the differences between the interventions at each time point. Twelve participants were randomized and analyzed for each sequence. PBMT-sMF enhanced the performance on functional tests (calculated as a percentage of change) when applied before or after WOD in the assessment performed immediately post-WOD and at 24 and 48 hours later (p < 0.05) compared to placebo and PBMT-sMF before and after WOD. In terms of the secondary outcomes, PBMT-sMF applied before or after WOD significantly decreased the creatine kinase, catalase, and superoxide dismutase activities and interleukin-6, thiobarbituric acid, and carbonylated protein levels (all p < 0.05) compared to the other possibilities of intervention. In addition, PBMT-sMF applied before and after WOD decreased creatine kinase activity at 24 hours and IL-6 levels at 24 and 48 hours compared to placebo (p < 0.05). None of the participants reported any adverse events. PBMT-sMF enhanced the performance of functional tests, decreased the levels of biochemical markers of muscle damage and inflammation, decreased oxidative stress, and increased antioxidant activity in CrossFit® athletes when applied before or after WOD.

Differential Ratings of Perceived Exertion: Relationships With External Intensity and Load in Elite Men's Football

PURPOSE

To examine the utility of differential ratings of perceived exertion (dRPE) for monitoring internal intensity and load in association football.

METHODS

Data were collected from 2 elite senior male football teams during 1 season (N = 55). External intensity and load data (duration × intensity) were collected during each training and match session using electronic performance and tracking systems. After each session, players rated their perceived breathlessness and leg-muscle exertion. Descriptive statistics were calculated to quantify how often players rated the 2 types of rating of perceived exertion differently (dRPEDIFF). In addition, the association between dRPEDIFF and external intensity and load was examined. First, the associations between single external variables and dRPEDIFF were analyzed using a mixed-effects logistic regression model. Second, the link between dRPEDIFF and session types with distinctive external profiles was examined using the Pearson chi-square test of independence.

RESULTS

On average, players rated their session perceived breathlessness and leg-muscle exertion differently in 22% of the sessions (range: 0%-64%). Confidence limits for the effect of single external variables on dRPEDIFF spanned across largely positive and negative values for all variables, indicating no conclusive findings. The analysis based on session type indicated that players differentiated more often in matches and intense training sessions, but there was no pattern in the direction of differentiation.

CONCLUSIONS

The findings of this study provide no evidence supporting the utility of dRPE for monitoring internal intensity and load in football.

The Current State of Subjective Training Load Monitoring: Follow-Up and Future Directions

This article addresses several key issues that have been raised related to subjective training load (TL) monitoring. These key issues include how TL is calculated if subjective TL can be used to model sports performance and where subjective TL monitoring fits into an overall decision-making framework for practitioners. Regarding how TL is calculated, there is conjecture over the most appropriate (1) acute and chronic period lengths, (2) smoothing methods for TL data and (3) change in TL measures (e.g., training stress balance (TSB), differential load, acute-to-chronic workload ratio). Variable selection procedures with measures of model-fit, like the Akaike Information Criterion, are suggested as a potential answer to these calculation issues with examples provided using datasets from two different groups of elite athletes prior to and during competition at the 2016 Olympic Games. Regarding using subjective TL to model sports performance, further examples using linear mixed models and the previously mentioned datasets are provided to illustrate possible practical interpretations of model results for coaches (e.g., ensuring TSB increases during a taper for improved performance). An overall decision-making framework for determining training interventions is also provided with context given to where subjective TL measures may fit within this framework and the determination if subjective measures are needed with TL monitoring for different sporting situations. Lastly, relevant practical recommendations (e.g., using validated scales and training coaches and athletes in their use) are provided to ensure subjective TL monitoring is used as effectively as possible along with recommendations for future research.

A lab-based comparison of differential ratings of perceived exertion between a run and jump protocol involving low or high impacts on the lower extremities

ABSTRACTThe rating of perceived exertion method allows to describe training intensity in a single value. To better understand the underlying components, the separate rating of perceived breathlessness (RPE-B) and leg-muscle exertion (RPE-L) has been proposed. Here we hypothesized that the separation between the two components may (partly) be determined by the impacts on the lower extremities. In this study, we aimed to experimentally evaluate the differential effect of high versus low impact running and jumping on RPE-B and RPE-L in team sport activities by manipulating the movement strategy (heel strike and passive landing pattern versus forefoot strike and active landing pattern). Eighteen recreational team sport players participated in two submaximal tests consisting of a sequence of running and jumping bouts, whilst ground reaction forces (GRF) were collected. RPE-B and RPE-L data were collected after each bout using the CR100 scale. Paired-samples t-tests were used to analyse between-session differences in these variables. GRF analysis showed that absorption mechanics differed considerably between the two sessions. RPE-L was on average 6.50 AU higher in the low impact session (p = 0.006). However, RPE-B was also increased by 4.96 AU with low impact (p = 0.009). We conclude that the extent to which the lower extremities are being exposed to high or low impacts does not explain a possible separation between the two RPE types.

Acute physiological and perceptual responses to a netball specific training session in professional female netball players

The 24 h responses to professional female netball-specific training were examined. British Superleague players (n = 14) undertook a 90-min on-court training session incorporating key movement, technical, and scenario-specific match-play drills. Perceptual (mood, fatigue, soreness), neuromuscular (countermovement jump peak power output [PPO], PPO relative to mass [PPOrel], jump height [JH]), endocrine (salivary cortisol [C], testosterone [T] concentrations) and biochemical (creatine kinase concentrations [CK]) markers were assessed at baseline (immediately before; Pre), and immediately, two and 24 hours after (+0h, +2h, +24h) training. Session (sRPE) and differential (dRPE) ratings of perceived exertion were recorded at +0h. Identification of clear between time-point differences were based on the 95% confidence interval (CI) for mean differences relative to baseline values not overlapping. At +0h, C (raw unit mean difference from baseline; 95% CI: 0.16; 0.06 to 0.25 μg·dl^-1), T (32; 20 to 45 pg⋅ml^–1), CK (39; 28 to 50 u·L^-1), PPOrel (2.4; 0.9 to 3.9 W·kg^-1) and PPO (169; 52 to 286 W) increased. At +2h, fatigue (15; 7 to 24 AU), CK (49; 38 to 60 u·L^-1), and soreness (14; 3 to 25 AU) increased, while T (-24; -37 to -11 pg⋅ml^–1) and mood (-20; -27 to -12 AU) reduced. At +24h, CK increased (25; 13 to 36 u·L^-1) whereas PPOrel (-1.6; -3.2 to -0.1 W·kg^-1) and JH (-0.02; -0.03 to -0.08 m) reduced. Responses were variable specific, and recovery of all variables did not occur within 24h. The residual effects of the prior stimulus should be accounted for in the planning of training for professional female netball players.

Wearable Inertial Measurement Unit to Measure External Load: A Full-Season Study in Professional Soccer Players

The aim of this study was to describe weekly acute workload (wAW), chronic workload (wCW), acute: chronic workload ratio (wACWR), training monotony (wTM), and training strain (wTS) variations over a full season across playing positions. Twenty-one professional soccer players were daily monitored during 48 consecutive weeks. Total distance, sprint total distance (STD), high-speed running distance (HSRd), maximum speed, number of the repeated sprints, and body load (BL) were obtained during training and matches using a Wearable Inertial Measurement Unit. The wAW was determined for each external load measure. The wCW, wACWR, and wTM were calculated based on BL metric. Higher values of weekly STD were observed in lateral defenders/wingers (LDW) compared to central defenders/forwards (CDF) (p = 0.009; ES = Large) and midfielders (MDF) (p = 0.034; ES = Large). Additionally, weekly HSRd was higher in LDW vs. CDF (p = 0.016; ES = Large) and MDF (p = 0.011; ES = Large). The CDF presented a lower weekly number of repeated sprints than LDW (p = 0.021; ES = Large). In conclusion, weekly external load metrics were position-dependent over the season. Moreover, LDW a presented greater weekly STD, HSRd, and number of repeated sprints compared to other positions.

Training Management of the Elite Adolescent Soccer Player throughout Maturation

Professional soccer clubs invest significantly into the development of their academy prospects with the hopes of producing elite players. Talented youngsters in elite development systems are exposed to high amounts of sports-specific practise with the aims of developing the foundational skills underpinning the capabilities needed to excel in the game. Yet large disparities in maturation status, growth-related issues, and highly-specialised sport practise predisposes these elite youth soccer players to an increased injury risk. However, practitioners may scaffold a performance monitoring and injury surveillance framework over an academy to facilitate data-informed training decisions that may not only mitigate this inherent injury risk, but also enhance athletic performance. Constant communication between members of the multi-disciplinary team enables context to build around an individual's training status and risk profile, and ensures that a progressive, varied, and bespoke training programme is provided at all stages of development to maximise athletic potential.

Nonergodicity in Load and Recovery: Group Results Do Not Generalize to Individuals

PURPOSE

The study of load and recovery gained significant interest in the last decades, given its important value in decreasing the likelihood of injuries and improving performance. So far, findings are typically reported on the group level, whereas practitioners are most often interested in applications at the individual level. Hence, the aim of the present research is to examine to what extent group-level statistics can be generalized to individual athletes, which is referred to as the "ergodicity issue." Nonergodicity may have serious consequences for the way we should analyze, and work with, load and recovery measures in the sports field.

METHODS

The authors collected load, that is, rating of perceived exertion × training duration, and total quality of recovery data among youth male players of a professional football club. This data were collected daily across 2 seasons and analyzed on both the group and the individual level.

RESULTS

Group- and individual-level analysis resulted in different statistical outcomes, particularly with regard to load. Specifically, SDs within individuals were up to 7.63 times larger than SDs between individuals. In addition, at either level, the authors observed different correlations between load and recovery.

CONCLUSIONS

The results suggest that the process of load and recovery in athletes is nonergodic, which has important implications for the sports field. Recommendations for training programs of individual athletes may be suboptimal, or even erroneous, when guided by group-level outcomes. The utilization of individual-level analysis is key to ensure the optimal balance of individual load and recovery.

Evaluation of cognitive load in team sports: literature review

In team sports, load management has become one of the most common areas of investigation, given that effective control over load is the key to being able to optimize performance and avoid injuries. Despite the constant evolution and innovation in the latest theories, we can see a clear tendency in load management that focuses on physiological and mechanical aspects and neglects its cognitive character, which generates the variability inherent in the performance of athletes in a changing environment. Indicators of response that inform methods of control over cognitive load can include cognitive, physiological and behavioral indicators. However, limited investigations exist to support the reliability of each indicator regarding cognitive load. For this reason, the objective of this literature review is to present strategies used to manage cognitive load in team sports, as well as the indicators utilized for such a proposition and their relationships in specific contexts.

Effects of and Response to Mechanical Loading on the Knee

Mechanical loading to the knee joint results in a differential response based on the local capacity of the tissues (ligament, tendon, meniscus, cartilage, and bone) and how those tissues subsequently adapt to that load at the molecular and cellular level. Participation in cutting, pivoting, and jumping sports predisposes the knee to the risk of injury. In this narrative review, we describe different mechanisms of loading that can result in excessive loads to the knee, leading to ligamentous, musculotendinous, meniscal, and chondral injuries or maladaptations. Following injury (or surgery) to structures around the knee, the primary goal of rehabilitation is to maximize the patient's response to exercise at the current level of function, while minimizing the risk of re-injury to the healing tissue. Clinicians should have a clear understanding of the specific injured tissue(s), and rehabilitation should be driven by knowledge of tissue-healing constraints, knee complex and lower extremity biomechanics, neuromuscular physiology, task-specific activities involving weight-bearing and non-weight-bearing conditions, and training principles. We provide a practical application for prescribing loading progressions of exercises, functional activities, and mobility tasks based on their mechanical load profile to knee-specific structures during the rehabilitation process. Various loading interventions can be used by clinicians to produce physical stress to address body function, physical impairments, activity limitations, and participation restrictions. By modifying the mechanical load elements, clinicians can alter the tissue adaptations, facilitate motor learning, and resolve corresponding physical impairments. Providing different loads that create variable tensile, compressive, and shear deformation on the tissue through mechanotransduction and specificity can promote the appropriate stress adaptations to increase tissue capacity and injury tolerance. Tools for monitoring rehabilitation training loads to the knee are proposed to assess the reactivity of the knee joint to mechanical loading to monitor excessive mechanical loads and facilitate optimal rehabilitation.

Latent variable dose-response modelling of external training load measures and musculoskeletal responses in elite rugby league players

Establishing dose-response relationships between training load and fatigue can help the planning of training. The aim was to establish the relative importance of external training load measurements to relate to the musculoskeletal response on a group and individual player level. Sixteen elite male rugby league players were monitored across three seasons. Two- to seven-day exponential weighted averages (EWMA) were calculated for total distance, and individualised speed thresholds (via 30-15 Intermittent Fitness Test) derived from global positioning systems. The sit and reach, dorsiflexion lunge, and adductor squeeze tests represented the musculoskeletal response. Partial least squares and repeated measures correlation analyses established the relative importance of training load measures and then investigated their relationship to the collective musculoskeletal response for individual players through the construction of latent variables. On a group level, 2- and 3-day EWMA total distance had the highest relative importance to the collective musculoskeletal response (p < 0.0001). However, the magnitude of relationships on a group (r value = 0.20) and individual (r value = 0.06) level were trivial to small. The lack of variability in the musculoskeletal response over time suggest practitioners adopting such measures to understand acute musculoskeletal fatigue responses should do so with caution.

Training Load Monitoring Considerations for Female Gaelic Team Sports: From Theory to Practice

Athlete monitoring enables sports science practitioners to collect information to determine how athletes respond to training loads (TL) and the demands of competition. To date, recommendations for females are often adapted from their male counterparts. There is currently limited information available on TL monitoring in female Gaelic team sports in Ireland. The collection and analysis of female athlete monitoring data can provide valuable information to support the development of female team sports. Athletic monitoring can also support practitioners to help minimize risk of excessive TL and optimize potential athletic performance. The aims of this narrative review are to provide: (i) an overview of TL athlete monitoring in female team sports, (ii) a discussion of the potential metrics and tools used to monitor external TL and internal TL, (iii) the advantages and disadvantages of TL modalities for use in Gaelic team sports, and (iv) practical considerations on how to monitor TL to aid in the determination of meaningful change with female Gaelic team sports athletes.

Influence of pitch size and goalkeepers on external and internal load during small-sided games in amateur soccer players

Purpose

To analyse the influence of goalkeepers during 4-a-side small-sided games, played in pitches of two different sizes (small: 30 × 20 m, large: 40 × 30 m).

Methods

Total distance covered (TD), distance covered at low- (LSD), moderate- (MSD), high- (HSD) and very high-speed (VHSD), average and maximal speed, Edwards’ training load (Edw-TL), time spent above 90% of maximal heart rate (T90%) and rate of perceived exertion (RPE) were monitored, in 18 amateur soccer players.

Results

Higher TD (mean difference: + 181 m, Hedge’s g: 0.93 and + 400 m, 3.37), MSD (+ 85 m, 0.79 and + 146 m, 1.64), HSD (+ 101 m, 1.41 and + 179 m, 3.26), VHSD (+ 30 m, 1.89 and + 35 m, 1.26), average speed (+ 0.65 km h−1, 0.88 and + 1.47 km h−1, 3.31) and maximal speed (+ 3.60 km h−1, 1.40 and + 3.58 km h−1, 1.40) were found in large than small pitch, without and with goalkeepers, respectively. Goalkeeper’s presence increased Edw-TL (+ 8.4 AU, 0.70) and reduced TD (− 141 m, 0.75), HSD (− 54 m, 0.75) and average speed (− 0.54 km h−1, 0.76) in small pitch and maximal speed (1.59 km h−1, 0.60 and 1.61 km h−1, 0.66) in both small and large pitches, respectively. RPE was higher (+ 20, 1.52) in the large than small pitch when the goalkeepers were present.

Conclusion

Implementing small-sided games, coaches should be aware that lower external load with similar internal load could be provided using small pitch with goalkeeper rather than either small goals or larger pitch. Furthermore, large small-sided games without goalkeeper may be the best choice for eliciting high training load.

Relationship Between Subjective and External Training Load Variables in Youth Soccer Players

PURPOSE

To quantify and describe relationships between subjective and external measures of training load in professional youth soccer players.

METHODS

Data from differential ratings of perceived exertion (dRPE) and 7 measures of external training load were collected from 20 professional youth soccer players over a 46-week season. Relationships were described by repeated-measures correlation, principal component analysis, and factor analysis with oblimin rotation.

RESULTS

Significant positive (.44 ≤ r ≤ .99; P < .001) within-individual correlations were obtained across dRPE and all external training load measures. Correlation magnitudes were found to decrease when training load variables were expressed per minute. Principal component analysis provided 2 components, which described 83.3% of variance. The first component, which described 72.9% of variance, was heavily loaded by all measures of training load, while the second component, which described 10.4% of the variance, appeared to have a split between objective and subjective measures of volume and intensity. Exploratory factor analysis identified 4 theoretical factors, with correlations between factors ranging from .5 to .8. These factors could be theoretically described as objective volume, subjective volume, objective running, and objective high-intensity measures. Removing dRPE measures from the analysis altered the structure of the model, providing a 3-factor solution.

CONCLUSIONS

The dRPE measures are significantly correlated with a range of external training load measures and with each other. More in-depth analysis showed that dRPE measures were highly related to each other, suggesting that, in this population, they would provide practitioners with similar information. Further analysis provided characteristic groupings of variables.

Identifying Contextual Influences on Training Load: An Example in Professional Rugby Union

ABSTRACT

Dalton-Barron, NE, McLaren, SJ, Black, CJ, Gray, M, Jones, B, and Roe, G. Identifying contextual influences on training load: an example in professional rugby union. J Strength Cond Res 35(2): 503-511, 2021-We aimed to investigate the contextual factors influencing training load (TL), as determined by session rating of perceived exertion (sRPE-TL), accumulated within a match-to-match microcycle in rugby union players. Session rating of perceived exertion-TL data were collected daily from 35 professional rugby union players from the same team in the English Championship over the course of an in-season period. Players were split by positional groups (backs and forwards) and sRPE-TL data were categorized as: field-based on-feet sRPE-TL (sRPEField-TL), gym-based sRPE-TL (sRPEGym-TL), and the total summation of both (sRPETotal-TL). Three 2-level linear mixed models were built for each dependent variable in each positional group, with magnitude-based inferences applied. Long between-match recovery cycles (≥7 days) resulted in very likely to almost certainly small to moderate increases in sRPE-TL for all modalities and positions (fixed effect [mean range] = 28.5%-42.0%), apart from sRPEField-TL for forwards. For backs, there was a very likely small decrease in sRPEField-TL as the season progressed (-16.7% per trimester). Losing the last league match was associated with very likely and almost certainly small decreases in sRPETotal-TL and sRPEGym-TL for backs (-20.7% and -36.4%, respectively). Losing the last match in any competition resulted in a very likely small increase in sRPEField-TL (21.2%) and a possibly small decrease sRPEGym-TL (-18.5%) for backs-with a likely smaller sRPEGym-TL for forwards (-33.4%). The strength of the upcoming opposition had no effect on sRPE-TL. Our findings highlight some of the multifactorial contextual factors that must be considered when planning and evaluating training microcycles.

Influence of Contextual Factors, Technical Performance, and Movement Demands on the Subjective Task Load Associated With Professional Rugby League Match-Play

PURPOSE

To identify the association between several contextual match factors, technical performance, and external movement demands on the subjective task load of elite rugby league players.

METHODS

Individual subjective task load, quantified using the National Aeronautics and Space Administration Task Load Index (NASA-TLX), was collected from 29 professional rugby league players from one club competing in the European Super League throughout the 2017 season. The sample consisted of 26 matches (441 individual data points). Linear mixed modeling revealed that various combinations of contextual factors, technical performance, and movement demands were associated with subjective task load.

RESULTS

Greater number of tackles (effect size correlation ± 90% confidence intervals; η2 = .18 ± .11), errors (η2 = .15 ± .08), decelerations (η2 = .12 ± .08), increased sprint distance (η2 = .13 ± .08), losing matches (η2 = .36 ± .08), and increased perception of effort (η2 = .27 ± .08) led to most likely-very likely increases in subjective total task load. The independent variables included in the final model for subjective mental demand (match outcome, time played, and number of accelerations) were unclear, excluding a likely small correlation with technical errors (η2 = .10 ± .08).

CONCLUSIONS

These data provide a greater understanding of the subjective task load and their association with several contextual factors, technical performance, and external movement demands during rugby league competition. Practitioners could use this detailed quantification of internal loads to inform recovery sessions and current training practices.

Testing protocol affects the velocity at VO2max in semi-professional soccer players

To compare three different protocols to assess the velocity associated with the maximal oxygen uptake (V_max) in soccer players. Sixteen semi-professional soccer players performed three maximum incremental tests on treadmill: two continuous protocols [1 km·h^-1·min^-1 (CP1); and 1 km·h^-1 every 2 min (CP2)], and one discontinuous (DP) protocol to determine V_max, maximum oxygen uptake (VO_2max) and oxygen cost of running (i.e., the slope of the VO₂ vs velocity relationship at submaximal exercise). V_max was higher in CP1> CP2> DP (19.4 ± 1.7, 17.4 ± 1.2, 16.1 ± 1.1 km·h^-1 for CP1, CP2, and DP, respectively; P < 0.05 ES: 0.09 to 3.36). No difference in VO_2max was found between CP1, CP2 and DP (P > 0.05). Oxygen cost of running showed between-protocol differences (CP1> CP2> DP; P < 0.05; ES: 0.28 to 3.30). V_max was higher when determined using continuous vs discontinuous protocols due to the greater overestimation in oxygen cost of running. Such differences in V_max should be considered to optimize acute physiological responses during high-intensity running activities.

The neuromuscular, physiological, endocrine and perceptual responses to different training session orders in international female netball players

AbstractThe 20 h responses of International female netball players to training days requiring two sessions (netball and strength, separated by two hours) ordered alternatively were examined. Eleven players completed strength followed by netball training two hours later (STR-NET), with the order reversed (NET-STR) on a separate day. Well-being, neuromuscular performance (jump height [JH], peak power output [PPO], peak velocity [PV]) and endocrine function (testosterone, cortisol concentrations) were measured before sessions one (PreS1) and two (PreS2), immediately after sessions one (IPS1) and two (IPS2), and 20 h post session one (20P). Session and differential ratings of perceived exertion (upper-body, cognitive/technical [RPE-T], lower-body, breathlessness) were collected, and accelerometry and heart rate measured netball load. Identification of clear between-order differences was based on the nonoverlap of the 95% confidence interval (95%CI) for mean differences relative to baseline. Compared to PreS1, greater increases in JH (percentage difference between trials; 95%CI: 9%; 4-14%), PPO (5%; 2-8%), PV (3%; 1-5%) and cortisol concentration (45%; 1-88%), and a greater decrease for testosterone/cortisol ratio (-35%; -72 to -2%) occurred at PreS2 in NET-STR. At 20P, greater decreases in JH (10%; 5-15%), PPO (4%; 1-8%) and PV (4%; 2-6%) were observed following STR-NET. No differences existed for well-being, whilst RPE-T was greater (15 AU; 3-26 AU) for strength training during NET-STR. Session order influenced neuromuscular and endocrine responses in International female netball players, highlighting session ordering as a key consideration when planning training.

Factors Influencing the Association Between Coach and Athlete Rating of Exertion: a Systematic Review and Meta-analysis

BACKGROUND

Subjective monitoring of rate of perceived exertion is common practice in many sports. Typically, the information is used to understand the training load and at times modify forthcoming sessions. Identifying the relationship between the athlete and coach's interpretation of training would likely further benefit understanding load management. The aim of this systematic review was to evaluate the relationship between coaches' rating of intended exertion (RIE) and/or rating of observed exertion (ROE) and athletes' reported rating of perceived exertion (RPE).

METHODS

The review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We conducted a search of Medline, Google Scholar, Science Direct, SPORTDiscus, and Web of Science databases. We assessed the correlation between coach-reported RIE and/or ROE and RPE. Assessment for risk of bias was undertaken using the Quality Appraisal for Reliability Studies (QAREL) checklist. Inclusion criteria were (1) male and/or female individuals, (2) individual and/or team sport active participants, and (3) original research article published in the English language.

RESULTS

Data from 19 articles were found to meet the eligibility criteria. A random effect meta-analysis based on 11 studies demonstrated a positive association of player vs. coach rating of RIE (r = 0.62 [95% CI 0.5 to 0.7], p < 0.001). The pooled correlation from 7 studies of player vs. coach rating on ROE was r = 0.64 95% CI (0.5 to 0.7), p < 0.001.

CONCLUSION

There was a moderate to high association between coach RIE and/or ROE and athlete-reported RPE and this association seems to be influenced by many factors. The suggestions we present in this review are based on imploring practitioners to consider a multi-modal approach and the implications of monitoring when using RPE.

TRIAL REGISTRATION

CRD42020193387.

Use of Rating of Perceived Exertion-Based Training Load in Elite Ice Hockey Training and Match-Play

ABSTRACT

Rago, V, Vigh-Larsen, JF, Deylami, K, Muschinsky, A, and Mohr, M. Use of rating of perceived exertion-based training load in elite ice hockey training and match-play. J Strength Cond Res XX(X): 000-000, 2020-Training load (TL) based on the subjective rating of perceived exertion (RPE) may be a useful athlete monitoring alternative when wearable technology is unavailable. The aim of this study was to examine the validity of RPE-based TL monitoring in elite ice hockey. A male ice hockey team (n = 18) was monitored using a 200-Hz accelerometer, heart rate (HR) and RPE (0-10 scale), throughout a 4-week competitive period (n = 309 individual observations). Session-RPE (RPE × duration) averaged 244.8 ± 135.2 and 728.6 ± 150.9 arbitrary units (AU) during practice sessions and during official games, respectively. The smallest worthwhile change was 19.8 AU. Within-individual correlations between session-RPE and total accelerations >0.5 m·s-2 (Acctot), accelerations >2 m·s-2 (Acc2), total decelerations >-0.5 m·s-2 (Dectot), decelerations < -2 m·s-2 (Dec2), time > 85% maximum HR, Edwards' TL, and modified training impulse were very large (r = 0.70-0.89; p < 0.001). In addition, correlations between RPE and measures of exercise intensity (Acctot per min, Acc2 per min, Dectot per min, mean HR, and peak HR) were small (r = 0.02-0.29; p < 0.05) except for Dec2 being unclear (p = 0.686). Differences in intensity parameters between RPE range (easy to very hard, 2-7 AU) were small (r = 0.22-0.31; p < 0.05). The session-RPE method can be used as a global indicator of TL in ice hockey. Specific ranges of time-motion and HR intensity variables can be demarcated between RPE categories (easy to very hard; 2-7 AU). Accounting for training volume (session-RPE) more accurately reflects objective methods of TL based on accelerative efforts and HR, than the RPE score (based on the perception of the intensity).

Variability of professional soccer players' perceived match load after successive matches

This study analyses the differential perceived match load accumulated by professional soccer players depending on their: (a) participation in several consecutive official matches within the same week (Pre_Cup, Cup, and Post_Cup), and (b) total match participation time (i.e. 90 min, 70-90 min and < 70 min). Participants were 21 Spanish Second Division professional soccer players (M age = 27.1, SD = 3.3 years; M body height = 182.1, SD = 3.9 cm; M body mass = 75.8, SD = 5.14 kg). There were no significant differences (p > 0.05) in dRPE-ML among Pre_Cup, Cup and Post_Cup matches or in dRPE-ML between teams that took part in two or three official matches within the same week or three official matches in 2-4 consecutive weeks. The results suggest that participating in several matches in the same week does not increase accumulated perceived exertion for professional soccer players.

The moderating impact of maturation on acute neuromuscular and psycho-physiological responses to simulated soccer activity in academy soccer players

AbstractResource constraints complicate load monitoring practices in some academies, which is problematic based on load-injury associations surrounding periods of rapid non-linear growth. Limited research has explored relationships between maturation and perceived psycho-physiological response to activity and associated neuromuscular performance changes. This study aimed to quantify neuromuscular and psycho-physiological responses to standardised activity and analyse whether dose-responses were moderated by maturation. Fifty-seven male soccer players (age: 14.1 ± 0.9 years; stature: 165 ± 10 cm; body mass, 57 ± 9 kg; percentage of predicted adult height 92.7 ± 5%) from two Elite Player Performance Plan (EPPP) academies completed the youth soccer-specific aerobic fitness test (Y-SAFT⁶⁰). Countermovement jump (CMJ), reactive strength index (RSI), absolute (ABS) and relative leg stiffness (REL) were measured pre-post the Y-SAFT⁶⁰ with playerload (PL), heart rate (HR), total distance (TD^ist) and differential ratings of perceived exertion (dRPE) used as markers of load and intensity. A moderation model was employed to analyse interactions of maturation as a continuous variable. Analysis indicated no significant interaction (p <0.05) between maturation and neuromuscular performance but RPE-Technical demonstrated significant interactions (p = 0.01). Slope analysis indicated four variables (PL, RSI, ABS and REL) that demonstrated significance at various stages of maturation, most notably aligning with peak height velocity (∼87-96% PAH). Tentatively, we propose that maturational developments in the neuromuscular system offer some mechanistic explanation to the varied dose-responses observed. It is therefore important that maturation is habitually considered within prescription of training programmes and that further empirical studies are completed to determine maturity specific dose-responses.Highlights Components of both neuromuscular performance and psycho-physiological response to simulated soccer was influenced by maturity status.Individuals more biologically developed are more capable of 'coping' with the biomechanical load of simulated soccer activity resulting in more favourable neuromuscular responses.The period surrounding peak height velocity appears to influence whole body load-response pathways resulting in altered movement patterns during this period.To minimise the impact of maturity status, practitioners can restrict activities that elicit high biomechanical load and introduce biologically categorised training activities.

Relationship Between Preseason Training Load, Match Performance, and Match Activities in Professional Rugby League

Crang, ZL, Hewitt, A, Scott, TJ, Kelly, VG, and Johnston, RD. Relationship between pre-season training load, match performance and match activities in professional rugby league. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to establish the relationship between preseason training loads, technical match performance, and physical match activities in rugby league. Twenty-two professional rugby league players (age: 24.7 ± 4.0 years; height: 184.3 ± 4.7 cm; and body mass: 101.1 ± 9.9 kg) participated in the study. Training loads and physical match activities were monitored using global positioning systems. Total distance (m), high-speed running distance (VT1IFT; distance covered above estimated first ventilatory threshold [≥68% of 30-15 intermittent fitness test]) and total session rating of perceived exertion from all field-based (32.5 ± 8.5) and gym-based sessions (39.1 ± 12.5) were used to quantify preseason loads. Physical match activities were measured as total and high-speed running distance relative to individual playing time, whereas technical match activities and performance scores were used to evaluate individual match performance. To examine the relationship between physical match activities, technical performance, and preseason load, Pearson's correlation coefficients were quantified for each in-season game before performing a Fisher Z Transformation. Preseason high-speed running distance was positively associated with high-speed match activities (r = 0.34-0.51), whereas negatively associated with technical performance scores (r = -0.51 to -0.35) and hit up m·min of match-play (r = -0.30 to -0.17). It seems high speed running performed in the preseason period positively influences in-season physical match activity profiles, however, are unlikely to positively impact technical match performance.

COMPARISON OF AEROBIC PERFORMANCE INDICATORS OF SOCCER AND FUTSAL ATHLETES

ABSTRACT Soccer and futsal have similar technical movements that are used within different spatial dimensions and game dynamics. The possible physiological differences between players of each sport were unknown. The main purpose of this study was to compare the maximum oxygen uptake (VO2max) and ventilatory thresholds (VT) of soccer and futsal players. VO2max and VT of 32 athletes (soccer: n = 15; futsal: n = 17) were obtained by ergospirometry in a progressive treadmill test. VO2max was similar between groups. VT occurred later and at higher running speeds in the soccer players. The similarities found in VO2max may be related to the fact that the evaluations were carried out in the pre-season. The fact that the VT was reached later in the soccer players suggests a longer capacity for aerobic exercise and greater resistance to lactate production. Moreover, soccer players appear to be conditioned to withstand increased running times and speeds, until exhaustion. Players of both sports reached the second VT at similar intensities, suggesting no prevalence of anaerobic metabolism. Soccer and futsal players have similar VO2max, but their VTs occur at different times, and at different running speeds. Level of Evidence III; Cross-sectional study.

The Physiological and Perceptual Effects of Stochastic Simulated Rugby League Match Play

PURPOSE

To examine responses to a simulated rugby league protocol designed to include more stochastic commands, and therefore require greater vigilance, than traditional team-sport simulation protocols.

METHODS

Eleven male university rugby players completed 2 trials (randomized and control [CON]) of a rugby league movement simulation protocol, separated by 7 to 10 d. The CON trial consisted of 48 repeated ∼115-s cycles of activity. The stochastic simulation (STOCH) was matched for the number and types of activity performed every 5.45 min in CON but included no repeated cycles of activity. Movement using GPS, heart rate, rating of perceived exertion, and Stroop test performance was assessed throughout. Maximum voluntary contraction peak torque, voluntary activation (in percentage), and global task load were assessed after exercise.

RESULTS

The mean mental demand of STOCH was higher than CON (effect size [ES] = 0.56; ±0.69). Mean sprint speed was higher in STOCH (22.5 [1.4] vs 21.6 [1.6] km·h-1, ES = 0.50; ±0.55), which was accompanied by a higher rating of perceived exertion (14.3 [1.0] vs 13.0 [1.4], ES = 0.87; ±0.67) and a greater number of errors in the Stroop test (10.3 [2.5] vs 9.3 [1.4] errors; ES = 0.65; ±0.83). Maximum voluntary contraction peak torque (CON = -48.4 [31.6] N·m and STOCH = -39.6 [36.6] N·m) and voluntary activation (CON = -8.3% [4.8%] and STOCH = -6.0% [4.1%]) was similarly reduced in both trials.

CONCLUSIONS

Providing more stochastic commands, which requires greater vigilance, might alter performance and associated physiological, perceptual, and cognitive responses to team-sport simulations.

Differential Ratings of Perceived Match and Training Exertion in Girls' Soccer

PURPOSE

To understand the validity of differential ratings of perceived exertion (dRPE) as a measure of girls' training and match internal loads.

METHODS

Using the centiMax scale (CR100), session dRPE for breathlessness (sRPE-B) and leg muscle exertion (sRPE-L) were collected across a season of training (soccer, resistance, and fitness) and matches from 33 players (15 [1] y). Differences and associations between dRPE were examined using mixed and general linear models. The authors' minimal practical important difference was 8 arbitrary units (AU).

RESULTS

Mean (AU [SD] ∼16) sRPE-B and sRPE-L were 66 and 61 for matches, 51 and 49 for soccer, 86 and 67 for fitness, and 45 and 58 for resistance, respectively. Session RPE-B was rated most likely harder than sRPE-L for fitness (19 AU; 90% confidence limits: ±7) and most likely easier for resistance (-13; ±2). Match (5; ±4) and soccer (-3; ±2) differences were likely to most likely trivial. The within-player relationships between sRPE-B and sRPE-L were very likely moderate for matches (r = .44; 90% confidence limits: ±.12) and resistance training (.38; ±.06), likely large for fitness training (.51; ±.22), and most likely large for soccer training (.56; ±.03). Shared variance ranged from 14% to 35%.

CONCLUSIONS

Practically meaningful differences between dRPE following physical training sessions coupled with low shared variance in all training types and matches suggest that sRPE-B and sRPE-L represent unique sensory inputs in girls' soccer players. The data provide evidence for the face and construct validity of dRPE as a measure of internal load in this population.

Use of Numerically Blinded Ratings of Perceived Exertion in Soccer: Assessing Concurrent and Construct Validity

PURPOSE

To examine the concurrent and construct validity of numerically blinded ratings of perceived exertion (RPEs).

METHODS

A total of 30 elite male youth soccer players (age 16.7 [0.5] y) were monitored during training and matches over a 17-wk in-season period. The players' external loads were determined via raw 10-Hz global positioning system. Heart rate (HR) was collected continuously and expressed as Bannister and Edwards training impulses, and minutes >80% of the players predetermined the maximum HR by the Yo-Yo Intermittent Recovery Test Level 1. RPE was collected confidentially 10 to 15 min after training/matches using 2 methods: (1) a traditional verbal response to the 0 to 100 category-ratio "centiMax" scale (RPE) and (2) numerically blinded RPE centiMax scale (RPEblind) with the response selected manually via a 5 × 7-in tablet "slider." The RPE and RPEblind were divided by 10 and multiplied by the duration to derive the sessional RPE. Linear mixed models compared ratings, and within-subject repeated-measures correlations assessed the sessional RPE versus HR and external load associations.

RESULTS

There were no differences between the RPE and RPEblind (0.19; 95% confidence intervals, -0.59 to 0.20 au, P = .326) or their session values (13.5; 95% confidence intervals, -17.0 to 44.0 au, P = .386), and the ratings were nearly perfectly correlated (r = .96). The associations between the sessional RPE versus HR and external load metrics were large to very large (r = .65-.81), with no differences between the RPE methods (P ≥ .50). The RPEblind also reduced verbal anchor clustering and integer bias by 11% and 50%, respectively.

CONCLUSIONS

RPEblind demonstrated concurrent and construct validity versus the traditional method, and may be used in situations where practitioners have concerns regarding the authenticity of athlete ratings.

Profiling the Post-match Recovery Response in Male Rugby: A Systematic Review

Aben, HGJ, Hills, SP, Cooke, CB, Davis, D, Jones, B, and Russell, M. Profiling the post-match recovery response in male rugby: A systematic review. J Strength Cond Res XX(X): 000-000, 2020-To minimize underperformance, injury, and illness, and to enhance readiness for training and match-play, post-match responses are commonly monitored within professional rugby. As no clear consensus exists regarding the magnitude and duration of post-match recovery, this review summarized the literature (17 studies yielded from literature searching/screening) reporting neuromuscular (countermovement jump [CMJ], peak power output [PP], and flight time [FT]), biochemical (creatine kinase [CK]) or endocrine (cortisol [C] and testosterone [T] concentrations), and subjective (wellness questionnaire and muscle soreness) indices after rugby match-play. For neuromuscular responses (11 studies), reductions in PP <31.5% occurred <30 minutes after match, returning to baseline within 48-72 hours. Post-match reductions in FT of <4% recovered after 48 hours. For biochemical and endocrine responses (14 studies), increases in CK, ranging from 120 to 451%, peaked between 12 and 24 hours, returning to baseline within 72 hours of match-play. Initial increases of <298% in C and reductions in T concentrations (<44%) returned to pre-match values within 48-72 hours. Mood disturbances (6 studies) required 48-72 hours to normalize after peak decrements of <65% at 24 hours. This review highlights that 72 hours were needed to restore perturbations in neuromuscular, biochemical and endocrine, and subjective/perceptual responses after competitive rugby match-play. Notably, only 4 studies reported responses in more ecologically valid scenarios (i.e., those in which regular training and recovery strategies were used) while also reporting detailed match demands. A lack of research focusing on youth players was also evident, as only 3 studies profiled post-match responses in younger athletes. Deeper insight regarding post-match responses in ecologically valid scenarios is therefore required.

Optimised force-velocity training during pre-season enhances physical performance in professional rugby league players

The effectiveness of 8-week force-velocity optimised training was assessed in highly trained professional rugby league athletes. Players (age 24 ± 3 years; body mass 94.9 ± 21.6 kg; height 181.3 ± 6.0 cm) were strength-matched and assigned to a force-velocity optimised group (OP; n = 15) or a general strength-power group (GP; n = 14). Tests included 10-m, 20-m sprints, 3 repetition-maximum squat and squat jumps over five load conditions to ascertain vertical force-velocity relationship. ANCOVA revealed there was a group effect for force-velocity deficit (P < 0.001), with the OP two-fold greater than the GP group (OP pre: 51.13 ± 31.42%, post: 62.26 ± 31.45%, GP pre: 33.00 ± 19.60%, post: 31.14 ± 31.45%, P < 0.001). There were further group effects for 3RM squat (OP pre: 151.17 ± 22.95 kg, post: 162.17 ± 24.16 kg, GP pre: 156.43 ± 25.07 kg, post: 163.39 ± 25.39 kg, P < 0.001), peak power (OP pre: 3195 ± 949 W, post: 3552 ± 1033 W, GP pre: 3468 ± 911 W, post: 3591 ± 936 W, P < 0.001), and SJ (OP pre: 39.79 ± 7.80 cm, post: 42.69 ± 7.83 cm, GP pre: 40.44 ± 6.23 cm, post: 41.14 ± 5.66 cm, P < 0.001). Prescribing F-V deficit training is superior for improving physical performance within highly trained RL players.

The Reliability of Neuromuscular and Perceptual Measures Used to Profile Recovery, and the Time-Course of such Responses following Academy Rugby League Match-Play

In professional academy rugby league (RL) players, this two-part study examined; A) the within- and between-day reliability of isometric mid-thigh pulls (IMTP), countermovement jumps (CMJ), and a wellness questionnaire (n = 11), and B) profiled the responses with acceptable reliability (no between-trial differences and between-day coefficient of variation (CV) ≤10% and intraclass correlation coefficient (ICC) ≥0.8) for 120 h (baseline: -3, +24, +48, +72, +96, +120 h) following RL match-play (n = 10). In part A, force at 200, and 250 ms, and peak force (PF) demonstrated acceptable within- (CV%: 3.67-8.41%, ICC: 0.89-0.93) and between-day (CV%: 4.34-8.62%, ICC: 0.87-0.92) reliability for IMTP. Most CMJ variables demonstrated acceptable within-day reliability (CV%: 3.03-7.34%, ICC: 0.82-0.98), but only six (i.e., flight-time, PF, peak power (PP), relative PP, velocity at take-off (VTO), jump-height (JH)) showed acceptable between-day reliability (CV%: 2.56-6.79%, ICC: 0.83-0.91). Only total wellness demonstrated acceptable between-day reliability (CV%: 7.05%, ICC: 0.90) from the questionnaire. In part B, reductions of 4.75% and 9.23% (vs. baseline; 2.54 m∙s-1; 0.33 m) occurred at +24 h for CMJ VTO, and JH, respectively. Acceptable reliability was observed in some, but not all, variables and the magnitude and time-course of post-match responses were test and variable specific. Practitioners should therefore be mindful of the influence that the choice of recovery monitoring tool may have upon the practical interpretation of the data.

The Validity of the Session Rating of Perceived Exertion Method for Measuring Internal Training Load in Professional Classical Ballet Dancers

The aim of this study was to investigate the convergent validity of session rating of perceived exertion (s-RPE) with objective measures of internal training load (TL) in professional classical ballet dancers. Heart rate and s-RPE data were collected in 22 professional classical ballet dancers across a total of 218 ballet class or rehearsal sessions. Eleven participants completed at least 9 sessions, and were therefore included in analyses of individual relationships between s-RPE and objective measures. To calculate s-RPE, the session duration was multiplied by the RPE, measured using the modified Borg CR-10 scale. The Edwards summated heart rate zones (Edwards TRIMP) and Banister training impulse (Banister TRIMP) methods were used as criterion measures of internal TL. Pearson product-moment correlation coefficients were used to determine intra-individual relationships between s-RPE and objective measures. Repeated measures correlations were used to identify intra-individual relationships common across the cohort. Positive linear relationships were seen between s-RPE and objective measures across all session types [Edwards TRIMP: r rm (195) = 0.81, p < 0.001; Banister TRIMP: r rm (195) = 0.79, p < 0.001], in ballet class [Edwards TRIMP: r rm (58) = 0.64, p < 0.001; Banister TRIMP: r rm (58) = 0.59, p < 0.001], and in rehearsals [Edwards TRIMP: r rm (119) = 0.82, p < 0.001; Banister TRIMP: r rm (119) = 0.80, p < 0.001], as well as across both males [Edwards TRIMP: r rm (136) = 0.82, p < 0.001; Banister TRIMP: r rm (136) = 0.80, p < 0.001], and females [Edwards TRIMP: r rm (57) = 0.80, p < 0.001; Banister TRIMP: r rm (57) = 0.78, p < 0.001]. Intra-individual correlation coefficients ranged from 0.46-0.96 [Edwards TRIMP: mean r = 0.81 ± 0.11, p = 0.051 - < 0.001; Banister TRIMP: mean r = 0.78 ± 0.14, p = 0.13- < 0.001]. These results demonstrate that s-RPE is a valid and practical method for measuring internal TL in professional classical ballet dancers.

Systematic Reductions in Differential Ratings of Perceived Exertion Across a 2-Week Repeated-Sprint-Training Intervention That Improved Soccer Players' High-Speed-Running Abilities

PURPOSE

To quantify changes in differential ratings of perceived exertion (dRPE) across a 2-wk repeated-sprint-training intervention that improved high-intensity intermittent-running ability and linear speed of semiprofessional soccer players.

METHODS

Thirteen players completed 3 (sessions 1-3) or 4 (sessions 4-6) sets of 7 sprints (group 1 [n = 7]: 30-m straight; group 2 [n = 6]: 2 × 10-m shuttle), with 20 s and 4 min of recovery between sprints and sets, respectively. Postset perceptions of breathlessness (RPE-B) and leg-muscle exertion (RPE-L) were rated using the CR100 scale.

RESULTS

Overall, RPE-B (mean [SD]: 46 [13] arbitrary units [AU], "hard") was most likely higher than RPE-L (39 [13] AU, "somewhat hard," mean difference: 8 AU; 90% confidence limits [CLs]: ±2). Set-to-set increases in dRPE (in AU; 90% CL: approximately ±2) were large in session 1 (RPE-B: 15; RPE-L: 14), moderate in sessions 2-5 (RPE-B: 7-10; RPE-L: 7-8), and small (RPE-B: 6) to moderate (RPE-L: 7) in session 6. Across the intervention, RPE-B reduced moderately in sets 3 (-13; 90% CL: ±4) and 4 (-12; 90% CL: ±12) and RPE-L reduced by a small magnitude in set 3 (-5; 90% CL: ±6). The set 4 change in RPE-L was unclear (-11; 90% CL: ±13).

CONCLUSIONS

The authors observed systematic intrasession and intersession changes in dRPE across a 2-wk repeated-sprint-training intervention, with a fixed prescription of external load that improved semiprofessional soccer players' high-speed-running abilities. These findings could support dRPE as a measure of internal load and highlight its usefulness in evaluating repeated-sprint-training dose-response.

“How Am I Going, Coach?”—The Effect of Augmented Feedback During Small-Sided Games on Locomotor, Physiological, and Perceptual Responses

Purpose: To investigate whether providing global positioning system feedback to players between bouts of small-sided games (SSGs) can alter locomotor, physiological, and perceptual responses. Methods: Using a reverse counterbalanced design, 20 male university rugby players received either feedback or no feedback during “off-side” touch rugby SSGs. Eight 5v5, 6 × 4-minute SSGs were played over 4 d. Teams were assigned to a feedback or no-feedback condition (control) each day, with feedback provided during the 2-min between-bouts rest interval. Locomotor, heart rate, and differential rating of perceived exertion of breathlessness and leg-muscle exertion were measured and analyzed using a linear mixed model. Outcomes were reported using effect sizes (ES) and 90% confidence intervals (CI), and then interpreted via magnitude-based decisions. Results: Very likely trivial to unclear differences at all time points were observed in heart rate and differential rating of perceived exertion measures. Possibly to very likely trivial effects were observed between conditions, including total distance (ES = 0.15; 90 CI, −0.03 to 0.34), high-speed distance (ES = −0.07; 90 CI, −0.27 to 0.13), and maximal sprint speed (ES = 0.11; 90% CI, −0.11 to 0.34). All within-bout comparisons showed very likely to unclear differences, apart from possible increases in low-speed distance in bout 2 (ES = 0.23; 90% CI, 0.01 to 0.46) and maximal sprint speed in bout 4 (ES = 0.21; 90% CI, −0.04 to 0.45). Conclusions: In this study, verbal feedback did not alter locomotor, physiological, or perceptual responses in rugby players during SSGs. This may be due to contextual factors (eg, opposition) or the type (ie, distance) or low frequency of feedback provided.